U.S. Pat. Nos. 5,760,088 and 5,523,487 disclose the use of various quaternary ammonium hydroxides and carbonates as wood preservatives and methods for their preparation. In particular, U.S. Pat. No. 5,760,088 teaches that C1–C20 alkyl or aryl-substituted alkyl, C8–C20 alkyl quaternary ammonium hydroxides can be prepared by reacting the corresponding quaternary ammonium chloride in a solvent comprising a C1–C4 normal alcohol.
U.S. Pat. No. 5,523,487 discloses the reaction of a C1–C20 alkyl or aryl-substituted alkyl, C8–C20 alkyl quaternary ammonium hydroxide with carbon dioxide to form a quaternary ammonium carbonate.
Ammoniacol copper quats (ACQs) are frequently used as wood preservatives. The “quat” (i.e., quaternary ammonium compound) is typically a quaternary ammonium chloride such as didecyldimethyl ammonium chloride (DDAC) or an alkyldimethylbenzyl ammonium chloride (ADBAC). Chloride quats, however, have recently been found to corrode wood treating equipment.